/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package axil.compiler.ast;

import axil.api.extend.Source;
import axil.compiler.Compilation;
import axil.compiler.Scope;
import axil.vm.opcode.Opcode;


/**
 * This object represents an AST node. This exists only during the compilation
 * stage and is discarded once the VM instructions are generated. This interface
 * is not intended to be implemented by host applications at this time. Use the
 * Axil.instance() method to obtain objects, as necessary.
 */
public interface Node extends Source {
	/**
	 * Get the identifier defined by this node. If this node does not define an
	 * identifier, then an exception is thrown.
	 */
	public String identity();

	/**
	 * Provide a brief description of what this node is. This should include the
	 * kind of thing it is, not the contents of the thing.
	 */
	public String what();


	/**
	 * Dump the content of this node to the diagnostic device. This is strictly
	 * for internal diagnostics, not for application use.
	 */
	public void dump(int indent);


	/**
	 * Compile this node, verifying correctness and performing any optimizations
	 * possible. The compilation context and scope given are never null but may
	 * not contain the desired functions and identifiers.
	 */
	public Node compile(Compilation context, Scope scope);

	/**
	 * Emit VM instructions that represents an executable version of this AST
	 * node. The instruction returned cannot be null. An exception is thrown if
	 * any latent defects in the AST are discovered.
	 */
	public Opcode emit();
}
